carb is sick at upper rpms (1 Viewer)

[JohnnyC]

look at this site for a pic:
parts breakdown


Float setting notes
1. Fuel pressure is critical to float spillage.
Redline recommends 2.5 to 3 lbs. ( you should have a fuel pressure regulator...mine is set at 3lbs)
2. For aggressive off-road float drop should be limited to 44 .5 mm max drop



your 55mm is alot...as reference the drop in this photo is 50mm

 

[cfdlighthouse]

look at this site for a pic:
parts breakdown


Float setting notes
1. Fuel pressure is critical to float spillage.
Redline recommends 2.5 to 3 lbs. ( you should have a fuel pressure regulator...mine is set at 3lbs)
2. For aggressive off-road float drop should be limited to 44 .5 mm max drop



your 55mm is alot...as reference the drop in this photo is 50mm

thanks,

i looked for a diagram like the one you showed and only found ones with no measurements. guess should have looked harder. okay so plan is to set float at diagram specs or should i set the max drop at 44. im not doing any crazy offroad stuff so is that necessary?????

thanks again,

dan

 

[cfdlighthouse]

max drop

okay,

i took the middle road. set the max drop at what came out to be 47.25mm. will highway test tomorrow.

 

[lehiguy]

okay. took the top off bowl was clean, filter clean, float was set at 44 mm when top held at verticle measured from gasket to bottom of float with seat touching the ball. is this the 44mm in need or is it measured different???

i assume primary and secondary jets in orange in bowl numbered 145 on engine side, 150 on tire side. idle jets in red circle numbered 774 engine side and 775 tire side

also replaced fuel pump and fuel filter. havent started yet cause am iffy on what float measurement should be ie points of where it should be taken from at verticle and when horizontal what should it be at full drop i have 55mm now from gasket to bottom of float when held horizontally?????.

thanks

Those that you have circled in red are the air corrector jets, part of the emulsion system the Webers use. They are not your problem. The idle jets are held in a brass fitting that screws into the side of the carb. Look for a large brass screw head on each side. They are different and do not interchange. Check them for debris that can obstruct fuel flow, but from your description of the problem, I don't think that is the issue. As a side note, in the absence of an actuall float setting measurement, most floats will be parallel to the top plate when they shut off fuel flow. Turn the thing upside down and have a look. The float and the top plate (air horn more correctly) shoud be almost parallel to each other. Just a rule of thumb.

 

[cfdlighthouse]

Those that you have circled in red are the air corrector jets, part of the emulsion system the Webers use. They are not your problem. The idle jets are held in a brass fitting that screws into the side of the carb. Look for a large brass screw head on each side. They are different and do not interchange. Check them for debris that can obstruct fuel flow, but from your description of the problem, I don't think that is the issue. As a side note, in the absence of an actuall float setting measurement, most floats will be parallel to the top plate when they shut off fuel flow. Turn the thing upside down and have a look. The float and the top plate (air horn more correctly) shoud be almost parallel to each other. Just a rule of thumb.

thanks

 

[lehiguy]

A closer look at your photos shows a very dirty carb! Get some carb cleaner and get it cleaned up. trying to tune a dirty carb is pointless. You're also leaking pretty badly from the valve cover. Have you fouled your plugs with that goo? If enough gets down the plug holes, it will cause issues.

 

[JohnnyC]

in post #18 i see a vac port with three nipples...does that have manifold vac?

does that lil thing have vac at all?

i pluged mine many years ago...and cant remember if it has vac?

 

[cfdlighthouse]

A closer look at your photos shows a very dirty carb! Get some carb cleaner and get it cleaned up. trying to tune a dirty carb is pointless. You're also leaking pretty badly from the valve cover. Have you fouled your plugs with that goo? If enough gets down the plug holes, it will cause issues.

carb was leaking when i got it due to loose stuff tighten all up and no more leaks, just got lazy and did not spray it off. yes the vc does leak going to replace the gasket when i do the valve adjustment.

not sure how the plugs fowl from the outside though????

Been wrenchin since i was able to hold one and never come across a plug that was fouled from a leaking valve cover. Not saying it couldnt happen but with properly installed plugs oil can't get in from the outside!!!

 

[lehiguy]

in post #18 i see a vac port with three nipples...does that have manifold vac?

does that lil thing have vac at all?

i pluged mine many years ago...and cant remember if it has vac?

As I recall they do not.

 

[lehiguy]

carb was leaking when i got it due to loose stuff tighten all up and no more leaks, just got lazy and did not spray it off. yes the vc does leak going to replace the gasket when i do the valve adjustment.

not sure how the plugs fowl from the outside though????

Been wrenchin since i was able to hold one and never come across a plug that was fouled from a leaking valve cover. Not saying it couldnt happen but with properly installed plugs oil can't get in from the outside!!!

My BMW did it. It will work it's way through the threads, causing a poor ground, and eventually foul the plug. It takes a while, but it can happen.

 

[cfdlighthouse]

As I recall they do not.

it is a ported switch, only has vacume if vac is applied

 

[FJ40Jim]

in post #18 i see a vac port with three nipples...does that have manifold vac?

Yes, it's screwed into the manifold, hence manifold vacuum.
W/ the weber it can be removed and replaced w/ a 1/8" pipe plug.

 

[FJ40Jim]

it is a ported switch, only has vacume if vac is applied

No, it is the source for powering the emission system.

Does your mom know you aren't telling the truth?

 

[cfdlighthouse]

No, it is the source for powering the emission system.

Does your mom know you aren't telling the truth?

I try and not let her know when i have been bad

well, now that i am supposed to have vacume there, i should replace it with the plug as suggested. i, and wrongly so, assumed it was a switch because when i sprayed carb cleaner around it there was no change in engine and put a vac guage on the ports individually while the others were plugged and no vacume was shown.

only here can someone see something that seems off, ask a question, provide advice, and bring awareness to what was unknown.

Thanks

 

[FJ40Jim]

If you bust the three pronged thingy open, you'll find a layer of fabric inside it. That's so when somebody inadvertently leaves a vac hose loose, the engine will not suck sand in there while crossing the sahara. Pretty nice of Toyota to think of us, eh?
That's why the parts listing calls the vac fitting "Filter".

Anyway, if it is not getting much/any vacuum, then it can be cleaned by removing the fitting and blowing backwards (from the threaded fitting, out the three ports) with shop air and carb cleaner. Then it should be able to flow air/vacuum again.

 

[cfdlighthouse]

If you bust the three pronged thingy open, you'll find a layer of fabric inside it. That's so when somebody inadvertently leaves a vac hose loose, the engine will not suck sand in there while crossing the sahara. Pretty nice of Toyota to think of us, eh?
That's why the parts listing calls the vac fitting "Filter".

Anyway, if it is not getting much/any vacuum, then it can be cleaned by removing the fitting and blowing backwards (from the threaded fitting, out the three ports) with shop air and carb cleaner. Then it should be able to flow air/vacuum again.

cool

thanks jim

 

[cfdlighthouse]

too much fuel????

I think the float is adjusted too high. i am getting a gas smell around the carb. pretty heavy did not happen until changed float range. gaskets are tight no exterior leakage. can the float allow too much gas in the bowl and spill over occur?????

Thanks
Dan

 

[FJ40Jim]

Yes, that is possible.

 

[cfdlighthouse]

Yes, that is possible.

thanks, will re adjust tonight and see where that leaves me.

 

[cfdlighthouse]

well finally got on the highway. most of my driving is in town. everything works like a charm. it appears after the new fuel pump, new filter and carb float adjustments all is good no flat spots no stumbles good power up hill so for those who said fuel supply i think it gets the prize. thanks to everyone who helped and provided the input i needed.

i do have one last question, what would cause the idle to fluctuate. some times it idles fine at 650 to 700 and some times it drops down in the 400 to 500 range until i drive it a bit. This is on a warmed up engine. carb uses electric choke and high idle cam works fine in the cold

i don't understand why there is no real idle consistancy ie the engine drops back to the same idle speed everytime??

Thanks again everyone
Dan